Overview
EN ISO 18473-1:2018 (ISO 18473-1:2015) specifies requirements and test methods for surface-treated nanoscale calcium carbonate (NCC) in powder form intended for sealant applications. Adopted by CEN from ISO, the standard defines the key material characteristics, sampling, test procedures (including whiteness determination), marking and test reporting to improve communication between suppliers and sealant formulators.
Key topics and technical requirements
- Scope: Surface-treated NCC powders for industrial sealants - properties that affect performance and processability.
- Nanoscale definition: Size range approximately 1 nm to 100 nm (ISO/TS 80004-2).
- Critical material properties (examples from the standard):
- Average crystal size (XRD): ≤ 100 nm.
- Specific surface area (BET, ISO 9277): ≥ 16 m2/g.
- Mass fraction of calcium carbonate: ≥ 85%.
- Insoluble residue in HCl: ≤ 0.5% (mass fraction).
- Oil absorption (DINP or linseed oil, ISO 787‑5): ≥ 23 ml/100 g.
- Particle size characterization: Mass- or number-based median particle sizes may be reported (centrifuge, TEM). Some particle-size requirements are optional or subject to agreement between parties.
- Surface treatment: NCC is commonly surface treated to render particles hydrophobic and improve dispersibility and polymer compatibility in organic sealant systems.
- Other parameters: Moisture, pH, MgCO3 content, whiteness - several are “to be agreed between interested parties” or measured per referenced ISO methods.
- Test methods and support: Normative references include ISO 9277 (BET), ISO 787 series (oil absorption, moisture, pH), ISO 3262‑1/6 (extender tests) and ISO 15528 (sampling). The standard also specifies sampling, marking and test report content.
Applications and users
- Practical uses: NCC covered by this standard is used as an extender/pigment in sealants to improve rheology (thixotropy), reinforcement, opacifying, flame resistance, durability and recyclability. It can constitute up to ~50% mass fraction in formulations.
- Who uses the standard: NCC manufacturers, chemical suppliers, sealant formulators, quality control laboratories, procurement teams, R&D groups and regulatory/compliance professionals benefit from the standard to ensure consistent material performance and clear supplier–customer specifications.
Related standards
This standard is essential when specifying or testing nanoscale calcium carbonate for sealants, ensuring reproducible material properties and reliable performance in construction, automotive and electronics sealing applications.